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1.
Article in English | MEDLINE | ID: mdl-37490015

ABSTRACT

CONTEXT: In continuing professional development (CPD), educators face the need to develop and implement innovative assessment strategies to adhere to accreditation standards and support lifelong learning. However, little is known about the development and validation of these assessment practices. We aimed to document the breadth and depth of what is known about the development and implementation of assessment practices within CPD activities. METHODS: We conducted a scoping review using the framework proposed by Arksey and O'Malley (2005) and updated in 2020. We examined five databases and identified 1733 abstracts. Two team members screened titles and abstracts for inclusion/exclusion. After data extraction, we conducted a descriptive analysis of quantitative data and a thematic analysis of qualitative data. RESULTS: A total of 130 studies were retained for the full review. Most reported assessments are written assessments (n = 100), such as multiple-choice items (n = 79). In 99 studies, authors developed an assessment for research purpose rather than for the CPD activity itself. The assessment validation process was detailed in 105 articles. In most cases, the authors examined the content with experts (n = 57) or pilot-tested the assessment (n = 50). We identified three themes: 1-satisfaction with assessment choices; 2-difficulties experienced during the administration of the assessment; and 3-complexity of the validation process. CONCLUSION: Building on the adage "assessment drives learning," it is imperative that the CPD practices contribute to the intended learning and limit the unintended negative consequences of assessment. Our results suggest that validation processes must be considered and adapted within CPD contexts.

2.
Perspect Med Educ ; 12(1): XX, 2023.
Article in English | MEDLINE | ID: mdl-37252269

ABSTRACT

Background & Need for Innovation: Appraising the quality of narratives used in assessment is challenging for educators and administrators. Although some quality indicators for writing narratives exist in the literature, they remain context specific and not always sufficiently operational to be easily used. Creating a tool that gathers applicable quality indicators and ensuring its standardized use would equip assessors to appraise the quality of narratives. Steps taken for Development and Implementation of innovation: We used DeVellis' framework to develop a checklist of evidence-informed indicators for quality narratives. Two team members independently piloted the checklist using four series of narratives coming from three different sources. After each series, team members documented their agreement and achieved a consensus. We calculated frequencies of occurrence for each quality indicator as well as the interrater agreement to assess the standardized application of the checklist. Outcomes of Innovation: We identified seven quality indicators and applied them on narratives. Frequencies of quality indicators ranged from 0% to 100%. Interrater agreement ranged from 88.7% to 100% for the four series. Critical Reflection: Although we were able to achieve a standardized application of a list of quality indicators for narratives used in health sciences education, it does not exclude the fact that users would need training to be able to write good quality narratives. We also noted that some quality indicators were less frequent than others and we suggested a few reflections on this.


Subject(s)
Medicine , Quality Indicators, Health Care , Humans , Narration
3.
NAR Genom Bioinform ; 4(4): lqac089, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36478959

ABSTRACT

Targeted DNA sequencing approaches will improve how the size of short tandem repeats is measured for diagnostic tests and preclinical studies. The expansion of these sequences causes dozens of disorders, with longer tracts generally leading to a more severe disease. Interrupted alleles are sometimes present within repeats and can alter disease manifestation. Determining repeat size mosaicism and identifying interruptions in targeted sequencing datasets remains a major challenge. This is in part because standard alignment tools are ill-suited for repetitive and unstable sequences. To address this, we have developed Repeat Detector (RD), a deterministic profile weighting algorithm for counting repeats in targeted sequencing data. We tested RD using blood-derived DNA samples from Huntington's disease and Fuchs endothelial corneal dystrophy patients sequenced using either Illumina MiSeq or Pacific Biosciences single-molecule, real-time sequencing platforms. RD was highly accurate in determining repeat sizes of 609 blood-derived samples from Huntington's disease individuals and did not require prior knowledge of the flanking sequences. Furthermore, RD can be used to identify alleles with interruptions and provide a measure of repeat instability within an individual. RD is therefore highly versatile and may find applications in the diagnosis of expanded repeat disorders and in the development of novel therapies.

4.
Acad Med ; 97(11): 1699-1706, 2022 11 01.
Article in English | MEDLINE | ID: mdl-35612917

ABSTRACT

PURPOSE: Narrative comments are increasingly used in assessment to document trainees' performance and to make important decisions about academic progress. However, little is known about how to document the quality of narrative comments, since traditional psychometric analysis cannot be applied. The authors aimed to generate a list of quality indicators for narrative comments, to identify recommendations for writing high-quality narrative comments, and to document factors that influence the quality of narrative comments used in assessments in higher education. METHOD: The authors conducted a scoping review according to Arksey & O'Malley's framework. The search strategy yielded 690 articles from 6 databases. Team members screened abstracts for inclusion and exclusion, then extracted numerical and qualitative data based on predetermined categories. Numerical data were used for descriptive analysis. The authors completed the thematic analysis of qualitative data with iterative discussions until they achieved consensus for the interpretation of the results. RESULTS: After the full-text review of 213 selected articles, 47 were included. Through the thematic analysis, the authors identified 7 quality indicators, 12 recommendations for writing quality narratives, and 3 factors that influence the quality of narrative comments used in assessment. The 7 quality indicators are (1) describes performance with a focus on particular elements (attitudes, knowledge, skills); (2) provides a balanced message between positive elements and elements needing improvement; (3) provides recommendations to learners on how to improve their performance; (4) compares the observed performance with an expected standard of performance; (5) provides justification for the mark/score given; (6) uses language that is clear and easily understood; and (7) uses a nonjudgmental style. CONCLUSIONS: Assessors can use these quality indicators and recommendations to write high-quality narrative comments, thus reinforcing the appropriate documentation of trainees' performance, facilitating solid decision making about trainees' progression, and enhancing the impact of narrative feedback for both learners and programs.


Subject(s)
Narration , Quality Indicators, Health Care , Humans , Feedback
5.
Hum Mol Genet ; 31(3): 386-398, 2022 02 03.
Article in English | MEDLINE | ID: mdl-34494094

ABSTRACT

Expanded CAG/CTG repeat disorders affect over 1 in 2500 individuals worldwide. Potential therapeutic avenues include gene silencing and modulation of repeat instability. However, there are major mechanistic gaps in our understanding of these processes, which prevent the rational design of an efficient treatment. To address this, we developed a novel system, ParB/ANCHOR-mediated Inducible Targeting (PInT), in which any protein can be recruited at will to a GFP reporter containing an expanded CAG/CTG repeat. Previous studies have implicated the histone deacetylase HDAC5 and the DNA methyltransferase DNMT1 as modulators of repeat instability via mechanisms that are not fully understood. Using PInT, we found no evidence that HDAC5 or DNMT1 modulate repeat instability upon targeting to the expanded repeat, suggesting that their effect is independent of local chromatin structure. Unexpectedly, we found that expanded CAG/CTG repeats reduce the effectiveness of gene silencing mediated by targeting HDAC5 and DNMT1. The repeat-length effect in gene silencing by HDAC5 was abolished by a small molecule inhibitor of HDAC3. Our results have important implications on the design of epigenome editing approaches for expanded CAG/CTG repeat disorders. PInT is a versatile synthetic system to study the effect of any sequence of interest on epigenome editing.


Subject(s)
Epigenome , Trinucleotide Repeat Expansion , Gene Silencing , Humans , Trinucleotide Repeats
6.
Acad Med ; 97(5): 747-757, 2022 05 01.
Article in English | MEDLINE | ID: mdl-34753858

ABSTRACT

PURPOSE: Progress testing is an increasingly popular form of assessment in which a comprehensive test is administered to learners repeatedly over time. To inform potential users, this scoping review aimed to document barriers, facilitators, and potential outcomes of the use of written progress tests in higher education. METHOD: The authors followed Arksey and O'Malley's scoping review methodology to identify and summarize the literature on progress testing. They searched 6 databases (Academic Search Complete, CINAHL, ERIC, Education Source, MEDLINE, and PsycINFO) on 2 occasions (May 22, 2018, and April 21, 2020) and included articles written in English or French and pertaining to written progress tests in higher education. Two authors screened articles for the inclusion criteria (90% agreement), then data extraction was performed by pairs of authors. Using a snowball approach, the authors also screened additional articles identified from the included reference lists. They completed a thematic analysis through an iterative process. RESULTS: A total of 104 articles were included. The majority of progress tests used a multiple-choice and/or true-or-false question format (95, 91.3%) and were administered 4 times a year (38, 36.5%). The most documented source of validity evidence was internal consistency (38, 36.5%). Four major themes were identified: (1) barriers and challenges to the implementation of progress testing (e.g., need for additional resources); (2) established collaboration as a facilitator of progress testing implementation; (3) factors that increase the acceptance of progress testing (e.g., formative use); and (4) outcomes and consequences of progress test use (e.g., progress testing contributes to an increase in knowledge). CONCLUSIONS: Progress testing appears to have a positive impact on learning, and there is significant validity evidence to support its use. Although progress testing is resource- and time-intensive, strategies such as collaboration with other institutions may facilitate its use.


Subject(s)
Delivery of Health Care , Knowledge , Humans
7.
J Huntingtons Dis ; 10(1): 123-148, 2021.
Article in English | MEDLINE | ID: mdl-33579861

ABSTRACT

At fifteen different genomic locations, the expansion of a CAG/CTG repeat causes a neurodegenerative or neuromuscular disease, the most common being Huntington's disease and myotonic dystrophy type 1. These disorders are characterized by germline and somatic instability of the causative CAG/CTG repeat mutations. Repeat lengthening, or expansion, in the germline leads to an earlier age of onset or more severe symptoms in the next generation. In somatic cells, repeat expansion is thought to precipitate the rate of disease. The mechanisms underlying repeat instability are not well understood. Here we review the mammalian model systems that have been used to study CAG/CTG repeat instability, and the modifiers identified in these systems. Mouse models have demonstrated prominent roles for proteins in the mismatch repair pathway as critical drivers of CAG/CTG instability, which is also suggested by recent genome-wide association studies in humans. We draw attention to a network of connections between modifiers identified across several systems that might indicate pathway crosstalk in the context of repeat instability, and which could provide hypotheses for further validation or discovery. Overall, the data indicate that repeat dynamics might be modulated by altering the levels of DNA metabolic proteins, their regulation, their interaction with chromatin, or by direct perturbation of the repeat tract. Applying novel methodologies and technologies to this exciting area of research will be needed to gain deeper mechanistic insight that can be harnessed for therapies aimed at preventing repeat expansion or promoting repeat contraction.


Subject(s)
Disease Models, Animal , Genes, Modifier/genetics , Genomic Instability/genetics , Huntington Disease/genetics , Myotonic Dystrophy/genetics , Trinucleotide Repeat Expansion/genetics , Animals
8.
Sci Adv ; 6(27): eaaz4012, 2020 07.
Article in English | MEDLINE | ID: mdl-32656337

ABSTRACT

Expanded CAG/CTG repeats underlie 13 neurological disorders, including myotonic dystrophy type 1 (DM1) and Huntington's disease (HD). Upon expansion, disease loci acquire heterochromatic characteristics, which may provoke changes to chromatin conformation and thereby affect both gene expression and repeat instability. Here, we tested this hypothesis by performing 4C sequencing at the DMPK and HTT loci from DM1 and HD-derived cells. We find that allele sizes ranging from 15 to 1700 repeats displayed similar chromatin interaction profiles. This was true for both loci and for alleles with different DNA methylation levels and CTCF binding. Moreover, the ectopic insertion of an expanded CAG repeat tract did not change the conformation of the surrounding chromatin. We conclude that CAG/CTG repeat expansions are not enough to alter chromatin conformation in cis. Therefore, it is unlikely that changes in chromatin interactions drive repeat instability or changes in gene expression in these disorders.

9.
Methods Mol Biol ; 2056: 255-268, 2020.
Article in English | MEDLINE | ID: mdl-31586353

ABSTRACT

Expanded CAG/CTG repeats are genetically unstable and, upon expression, cause neurological and neuromuscular diseases. The molecular mechanisms of repeat instability and expression remain poorly understood despite their importance for the pathogenesis of a family of 14 devastating human diseases. This is in part because conventional assays are tedious and time-consuming. Recently, however, GFP-based reporters have been designed to provide a rapid and reliable means of assessing these parameters. Here we provide protocols for quantifying repeat instability and expression using a GFP-based chromosomal reporter and the newly developed ParB/ANCHOR-mediated Inducible Targeting (PInT) and how to validate the results.


Subject(s)
Green Fluorescent Proteins/genetics , Trinucleotide Repeats , Cell Line , Gene Expression , Genes, Reporter , Genomic Instability , Humans
10.
Sci Rep ; 9(1): 23, 2019 01 10.
Article in English | MEDLINE | ID: mdl-30631115

ABSTRACT

We present µLAS, a lab-on-chip system that concentrates, separates, and detects DNA fragments in a single module. µLAS speeds up DNA size analysis in minutes using femtomolar amounts of amplified DNA. Here we tested the relevance of µLAS for sizing expanded trinucleotide repeats, which cause over 20 different neurological and neuromuscular disorders. Because the length of trinucleotide repeats correlates with the severity of the diseases, it is crucial to be able to size repeat tract length accurately and efficiently. Expanded trinucleotide repeats are however genetically unstable and difficult to amplify. Thus, the amount of amplified material to work with is often limited, making its analysis labor-intensive. We report the detection of heterogeneous allele lengths in 8 samples from myotonic dystrophy type 1 and Huntington disease patients with up to 750 CAG/CTG repeats in five minutes or less. The high sensitivity of the method allowed us to minimize the number of amplification cycles and thus reduce amplification artefacts without compromising the detection of the expanded allele. These results suggest that µLAS can speed up routine molecular biology applications of repetitive sequences and may improve the molecular diagnostic of expanded repeat disorders.


Subject(s)
Diagnostic Tests, Routine/methods , Nervous System Diseases/diagnosis , Neuromuscular Diseases/diagnosis , Trinucleotide Repeat Expansion , Humans , Lab-On-A-Chip Devices , Nervous System Diseases/pathology , Neuromuscular Diseases/pathology , Sensitivity and Specificity
11.
Sci Rep ; 7(1): 18026, 2017 12 21.
Article in English | MEDLINE | ID: mdl-29269788

ABSTRACT

Expanded CAG/CTG repeats underlie the aetiology of 14 neurological and neuromuscular disorders. The size of the repeat tract determines in large part the severity of these disorders with longer tracts causing more severe phenotypes. Expanded CAG/CTG repeats are also unstable in somatic tissues, which is thought to modify disease progression. Routine molecular biology applications involving these repeats, including quantifying their instability, are plagued by low PCR yields. This leads to the need for setting up more PCRs of the same locus, thereby increasing the risk of carry-over contamination. Here we aimed to reduce this risk by pre-treating the samples with a Uracil N-Glycosylase (Ung) and using dUTP instead of dTTP in PCRs. We successfully applied this method to the PCR amplification of expanded CAG/CTG repeats, their sequencing, and their molecular cloning. In addition, we optimized the gold-standard method for measuring repeat instability, small-pool PCR (SP-PCR), such that it can be used together with Ung and dUTP-containing PCRs, without compromising data quality. We performed SP-PCR on myotonic-dystrophy-derived samples containing an expansion as large as 1000 repeats, demonstrating the applicability to clinically-relevant material. Thus, we expect the protocols herein to be applicable for molecular diagnostics of expanded repeat disorders.


Subject(s)
Polymerase Chain Reaction/methods , Trinucleotide Repeat Expansion , Humans , Myotonic Dystrophy/genetics
12.
Nat Commun ; 7: 13272, 2016 11 09.
Article in English | MEDLINE | ID: mdl-27827362

ABSTRACT

CAG/CTG repeat expansions cause over 13 neurological diseases that remain without a cure. Because longer tracts cause more severe phenotypes, contracting them may provide a therapeutic avenue. No currently known agent can specifically generate contractions. Using a GFP-based chromosomal reporter that monitors expansions and contractions in the same cell population, here we find that inducing double-strand breaks within the repeat tract causes instability in both directions. In contrast, the CRISPR-Cas9 D10A nickase induces mainly contractions independently of single-strand break repair. Nickase-induced contractions depend on the DNA damage response kinase ATM, whereas ATR inhibition increases both expansions and contractions in a MSH2- and XPA-dependent manner. We propose that DNA gaps lead to contractions and that the type of DNA damage present within the repeat tract dictates the levels and the direction of CAG repeat instability. Our study paves the way towards deliberate induction of CAG/CTG repeat contractions in vivo.


Subject(s)
CRISPR-Cas Systems , DNA Breaks, Single-Stranded , DNA Repair , Deoxyribonuclease I/metabolism , Trinucleotide Repeat Expansion/genetics , DNA/genetics , DNA/metabolism , Genomic Instability , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , HEK293 Cells , Humans , MutS Homolog 2 Protein/genetics , MutS Homolog 2 Protein/metabolism , Trinucleotide Repeats/genetics
13.
Genes Dev ; 29(10): 1006-17, 2015 May 15.
Article in English | MEDLINE | ID: mdl-25940904

ABSTRACT

Secondary structure-forming DNA sequences such as CAG repeats interfere with replication and repair, provoking fork stalling, chromosome fragility, and recombination. In budding yeast, we found that expanded CAG repeats are more likely than unexpanded repeats to localize to the nuclear periphery. This positioning is transient, occurs in late S phase, requires replication, and is associated with decreased subnuclear mobility of the locus. In contrast to persistent double-stranded breaks, expanded CAG repeats at the nuclear envelope associate with pores but not with the inner nuclear membrane protein Mps3. Relocation requires Nup84 and the Slx5/8 SUMO-dependent ubiquitin ligase but not Rad51, Mec1, or Tel1. Importantly, the presence of the Nup84 pore subcomplex and Slx5/8 suppresses CAG repeat fragility and instability. Repeat instability in nup84, slx5, or slx8 mutant cells arises through aberrant homologous recombination and is distinct from instability arising from the loss of ligase 4-dependent end-joining. Genetic and physical analysis of Rad52 sumoylation and binding at the CAG tract suggests that Slx5/8 targets sumoylated Rad52 for degradation at the pore to facilitate recovery from acute replication stress by promoting replication fork restart. We thereby confirmed that the relocation of damage to nuclear pores plays an important role in a naturally occurring repair process.


Subject(s)
DNA Repair/genetics , Nuclear Pore/metabolism , Recombination, Genetic , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/physiology , Trinucleotide Repeats/genetics , Protein Transport , S Phase , Saccharomyces cerevisiae/genetics , Sumoylation
14.
Methods Mol Biol ; 1292: 77-96, 2015.
Article in English | MEDLINE | ID: mdl-25804749

ABSTRACT

Fluorescence microscopy has enabled the analysis of both the spatial distribution of DNA damage and its dynamics during the DNA damage response (DDR). Three microscopic techniques can be used to study the spatiotemporal dynamics of DNA damage. In the first part we describe how we determine the position of DNA double-strand breaks (DSBs) relative to the nuclear envelope. The second part describes how to quantify the co-localization of DNA DSBs with nuclear pore clusters, or other nuclear subcompartments. The final protocols describe methods for the quantification of locus mobility over time.


Subject(s)
Saccharomycetales/genetics , Saccharomycetales/metabolism , DNA Breaks, Double-Stranded , DNA Damage/genetics , DNA Repair/genetics
15.
Mol Cell ; 55(4): 626-39, 2014 Aug 21.
Article in English | MEDLINE | ID: mdl-25066231

ABSTRACT

Persistent DNA double-strand breaks (DSBs) are recruited to the nuclear periphery in budding yeast. Both the Nup84 pore subcomplex and Mps3, an inner nuclear membrane (INM) SUN domain protein, have been implicated in DSB binding. It was unclear what, if anything, distinguishes the two potential sites of repair. Here, we characterize and distinguish the two binding sites. First, DSB-pore interaction occurs independently of cell-cycle phase and requires neither the chromatin remodeler INO80 nor recombinase Rad51 activity. In contrast, Mps3 binding is S and G2 phase specific and requires both factors. SWR1-dependent incorporation of Htz1 (H2A.Z) is necessary for break relocation to either site in both G1- and S-phase cells. Importantly, functional assays indicate that mutations in the two sites have additive repair defects, arguing that the two perinuclear anchorage sites define distinct survival pathways.


Subject(s)
Binding Sites/genetics , Chromatin Assembly and Disassembly/physiology , DNA, Fungal/genetics , Fungal Proteins/physiology , Saccharomycetales/genetics , Adenosine Triphosphatases/physiology , Binding Sites/physiology , Cell Cycle/genetics , Cell Cycle/physiology , Chromatin Assembly and Disassembly/genetics , DNA Breaks, Double-Stranded , Histones/metabolism , Membrane Proteins/metabolism , Mutation , Saccharomycetales/metabolism
16.
Trends Genet ; 30(6): 220-9, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24842550

ABSTRACT

DNA must constantly be repaired to maintain genome stability. Although it is clear that DNA repair reactions depend on cell type and developmental stage, we know surprisingly little about the mechanisms that underlie this tissue specificity. This is due, in part, to the lack of adequate study systems. This review discusses recent progress toward understanding the mechanism leading to varying rates of instability at expanded trinucleotide repeats (TNRs) in different tissues. Although they are not DNA lesions, TNRs are hotspots for genome instability because normal DNA repair activities cause changes in repeat length. The rates of expansions and contractions are readily detectable and depend on cell identity, making TNR instability a particularly convenient model system. A better understanding of this type of genome instability will provide a foundation for studying tissue-specific DNA repair more generally, which has implications in cancer and other diseases caused by mutations in the caretakers of the genome.


Subject(s)
DNA Repair , Organ Specificity/genetics , Animals , DNA Damage , Genomic Instability , Humans , Trinucleotide Repeats
17.
Nucleic Acids Res ; 42(8): 4985-95, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24574527

ABSTRACT

Various topological constraints at the ribosomal DNA (rDNA) locus impose an extra challenge for transcription and DNA replication, generating constant torsional DNA stress. The topoisomerase Top1 is known to release such torsion by single-strand nicking and re-ligation in a process involving transient covalent Top1 cleavage complexes (Top1cc) with the nicked DNA. Here we show that Top1ccs, despite their usually transient nature, are specifically targeted to and stabilized at the ribosomal replication fork barrier (rRFB) of budding yeast, establishing a link with previously reported Top1 controlled nicks. Using ectopically engineered rRFBs, we establish that the rRFB sequence itself is sufficient for induction of DNA strand-specific and replication-independent Top1ccs. These Top1ccs accumulate only in the presence of Fob1 and Tof2, they are reversible as they are not subject to repair by Tdp1- or Mus81-dependent processes, and their presence correlates with Top1 provided rDNA stability. Notably, the targeted formation of these Top1ccs accounts for the previously reported broken replication forks at the rRFB. These findings implicate a novel and physiologically regulated mode of Top1 action, suggesting a mechanism by which Top1 is recruited to the rRFB and stabilized in a reversible Top1cc configuration to preserve the integrity of the rDNA.


Subject(s)
DNA Replication , DNA Topoisomerases, Type I/metabolism , DNA, Ribosomal/biosynthesis , DNA Breaks, Double-Stranded , DNA Cleavage , DNA, Ribosomal/metabolism , DNA-Binding Proteins/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Protein Stability , RecQ Helicases/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism
19.
Genes Dev ; 27(18): 1999-2008, 2013 Sep 15.
Article in English | MEDLINE | ID: mdl-24029917

ABSTRACT

Double-strand break repair by recombination requires a homology search. In yeast, induced breaks move significantly more than undamaged loci. To examine whether DNA damage provokes an increase in chromatin mobility generally, we tracked undamaged loci under DNA-damaging conditions. We found that the yeast checkpoint factors Mec1, Rad9, and Rad53 are required for genome-wide increases in chromatin mobility, but not the repair protein Rad51. Mec1 activation by targeted Ddc1/Ddc2 enhances chromatin mobility even in the absence of damage. Finally, the INO80 chromatin remodeler is shown to act downstream from Mec1 to increase chromatin mobility, highlighting an additional damage-related role of this nucleosome remodeling complex.


Subject(s)
Cell Cycle Proteins/metabolism , Chromatin/metabolism , DNA Damage , Phosphotransferases/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Cell Cycle Checkpoints/physiology , Cell Cycle Proteins/genetics , Genome, Fungal/genetics , Models, Biological , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/genetics
20.
EMBO Rep ; 14(11): 984-91, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24018421

ABSTRACT

The regulation of chromatin mobility in response to DNA damage is important for homologous recombination in yeast. Anchorage reduces rates of recombination, whereas increased chromatin mobility correlates with more efficient homology search. Here we tracked the mobility and localization of spontaneous S-phase lesions bound by Rad52, and find that these foci have reduced movement, unlike enzymatically induced double-strand breaks. Moreover, spontaneous repair foci are positioned in the nuclear core, abutting the nucleolus. We show that cohesin and nucleolar integrity constrain the mobility of these foci, consistent with the notion that spontaneous, S-phase damage is preferentially repaired from the sister chromatid.


Subject(s)
Cell Cycle Proteins/metabolism , Cell Nucleolus/metabolism , Chromosomal Proteins, Non-Histone/metabolism , DNA Repair , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/metabolism , Chromatids/metabolism , DNA Damage , Homologous Recombination , Rad52 DNA Repair and Recombination Protein/metabolism , Recombinant Fusion Proteins/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Cohesins
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